The Republican Ehrlich said he opposes the country's move toward what he described as a European-style health care system that is deeply flawed and unaffordable.

O'Malley, a Democrat, supports the legislation, and said he wants Maryland to be a leader in implementing the reforms.

The debate is the first radio debate between the two in this year's race. A fourth debate on Washington's WTOP-FM previously scheduled for Friday has been postponed. The station said it's working with the candidates to reschedule it for next week.